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Laryngeal mask airway: a more successful method of insertion
B F Matta1, D S Marsh, M Nevin
1Sir Humphry Davy Department of Anaesthesia, Bristol Royal Infirmary, U.K.
Study Objective:
To compare the ease of insertion of the laryngeal mask airway (LMA) by two methods.
Design:
Prospective, randomized study.
Setting:
Operating room of a university-affiliated teaching hospital.
Patients:
350 ASA I, II, and III patients undergoing general anesthesia, in whom use of the LMA was not contraindicated.
Interventions:
With all routine monitors in place and after the induction of anesthesia with propofol, we compared the ease of insertion of the LMA in the two groups of 175 patients each. The timing of insertion was made on clinical grounds. In one group, the LMA was inserted with the cuff fully deflated, in the other group, the cuff was partially inflated (i.e., filled with half the recommended air in the cuff). When correct placement of the mask was not successful by one method, the other method was tried and the insertion graded in the same manner.
Measurements And Main Results:
The ease of insertion of the LMA was graded by the user on a scale of 1-4. Insertion of the LMA with the cuff partially inflated was significantly more successful (97.7%) than when the cuff was fully deflated (92%) (p < 0.05). When correct placement of the mask was not possible with the cuff fully deflated, partial inflation resulted in correct placement.
Conclusions:
Inserting the LMA with the cuff partially inflated is likely to be more successful than with the cuff fully deflated. When it is not possible to insert the LMA with the cuff fully deflated, partial inflation before insertion may result in correct placement.